Phase 2 new replication work:
* Removes old replication.proto file, old command_transform library
* Removes use of korr.h macro calls in favor of GPB's CodedOutputStream
API.
* Updates transaction_log, default_replicator, and filtered_replicator module
to use new Transaction message.
* Updates ReplicationServices to construct the new Transaction messages and
associated Statement sub-messages
* Corrects transaction boundaries. AUTOCOMMIT now works properly, and I have
added a new test case to verify AUTOCOMMIT variable modification of the way
in which Transaction messages are bundled up and sent across to replicators.